use std::ops::Deref;

use super::codec::Codec;
use crate::{ffi::*, format, Rational};

#[derive(PartialEq, Eq, Copy, Clone)]
pub struct Video {
	codec: Codec,
}

impl Video {
	pub unsafe fn new(codec: Codec) -> Video {
		Video { codec }
	}
}

impl Video {
	pub fn frame_rates(&self) -> Option<RateIter> {
		unsafe {
			if (*self.codec.as_ptr()).supported_framerates.is_null() {
				None
			}
			else {
				Some(RateIter::new((*self.codec.as_ptr()).supported_framerates))
			}
		}
	}

	pub fn formats(&self) -> Option<FormatIter> {
		unsafe {
			if (*self.codec.as_ptr()).pix_fmts.is_null() {
				None
			}
			else {
				Some(FormatIter::new((*self.codec.as_ptr()).pix_fmts))
			}
		}
	}
}

impl Deref for Video {
	type Target = Codec;

	fn deref(&self) -> &Self::Target {
		&self.codec
	}
}

pub struct RateIter {
	ptr: *const AVRational,
}

impl RateIter {
	pub fn new(ptr: *const AVRational) -> Self {
		RateIter { ptr }
	}
}

impl Iterator for RateIter {
	type Item = Rational;

	fn next(&mut self) -> Option<<Self as Iterator>::Item> {
		unsafe {
			if (*self.ptr).num == 0 && (*self.ptr).den == 0 {
				return None;
			}

			let rate = (*self.ptr).into();
			self.ptr = self.ptr.offset(1);

			Some(rate)
		}
	}
}

pub struct FormatIter {
	ptr: *const AVPixelFormat,
}

impl FormatIter {
	pub fn new(ptr: *const AVPixelFormat) -> Self {
		FormatIter { ptr }
	}
}

impl Iterator for FormatIter {
	type Item = format::Pixel;

	fn next(&mut self) -> Option<<Self as Iterator>::Item> {
		unsafe {
			if *self.ptr == AVPixelFormat::AV_PIX_FMT_NONE {
				return None;
			}

			let format = (*self.ptr).into();
			self.ptr = self.ptr.offset(1);

			Some(format)
		}
	}
}
